The co-existence of humans and wild birds has always been an important relationship for both species. For humans, this relationship has been a pleasant one esthetically and a useful one ecologically. In the former case, the sights and sounds of birds are universally enjoyed by people of all ages. In the latter case, the role of birds in the ecological chain vis-a-vis birds, carrion and other species is essential. It is, of course, essential that both relationships be preserved.
Notwithstanding the beneficial and pleasant aspects of the interface between wild birds and humans, the propensity of birds to alight on, occupy and damage solid surfaces associated with or near human activity frequently becomes a source of conflict.
A source of conflict between birds and humans is associated with areas of grassy turf on or around which there is substantial human activity, for example, birds can frequently become a nuisance and cause substantial damage to pedestrian traveled areas, such as golf courses, cemeteries and campuses. These areas, which require substantial upkeep, especially golf courses, suffer much due to birds nesting and gathering on them. For example, they can become a distraction because of the noise a flock can generate. Birds also become a nuisance because of the fecal deposits they leave. Fecal deposits are not only a nuisance due to the mess they cause, but also a public health concern due to the parasites and/or the disease that live in and spread from the droppings.
Another area of major concern is roosting birds near the end of runways at commercial and military airports. Roosting birds can cause "bird strikes" whereby many birds take flight near aircraft that are taking off or landing, which result in birds colliding with the aircraft or being sucked into the engines. This causes damage to the aircraft by damaging the canopy or the wings and engines. In some instances, birds have caused aircraft engines to fail completely and the plane to crash, which results in complete loss of the aircraft and in some instances has resulted in loss of human life. The Federal Aviation Administration receives as many as 2,000 reports of bird strikes each year. Major airlines report they sustain over $12 million of damage per year. Roosting birds like the open spaces around the runways. Due to this fact, approximately ninety percent of the bird strike damages occur around airports. Statistics show that bird strikes are growing in number due to (1) the increase in bird population, (2) nesting of more birds in urban areas, (3) fewer natural predators of birds, and (4) the marginal effectiveness of common bird harassment techniques. Bird strikes therefore remain a very dangerous and costly problem.
A further example of the problems, which can arise at the interface between birds and humans, are the effects of the presence of birds in areas for public gatherings.
For example, the ubiquitous presence of bird feces in public places presents problems of sanitation for people. Furthermore, the deposition of bird feces on metal surfaces often causes problems of corrosion. Birds, such as woodpeckers, also frequently cause damage to woody and other non-metal surfaces by pecking on them. Birds are also frequent inhabitants of the exposed steel and concrete framework of structures, such as sports arenas and aircraft hangars, from which their feces present problems to both equipment and people. In addition, roof damage often occurs at locations where the flashing becomes corroded by bird feces.
Over the course of many years, a large number of procedures have been suggested and tried to overcome the above-described problems associated with birds and man-made structural surfaces. However, these have largely had only limited success. One example of such devices is an ultrasonic device which birds, but not humans, can hear. Another approach is to coat the problem surfaces with a sticky liquid or gelatin which birds find uncomfortable. Of course, the classic bird repellent method is the use of scarecrows or other arrangements which are frightening to the birds by virtue of their appearance and movement. A still further technique is the use of replicas of predators such as hawks, eagles and owls. Flashing lights have also been used for this purpose. Even the sound of cannons has been used. None of these, however, has been sufficiently effective because (1) the deterrent effect does not last long; (2) they are expensive to run; (3) they constitute a nuisance to humans in the vicinity; or (4) they require too frequent maintenance.
Therefore, a serious need continues for a reliable and economical method to deter birds from alighting on, occupying and damaging plant and structural surfaces in such manner that neither the environment nor the birds are harmed.